Depending on sequence, bacterial and synthetic DNAs can activate the host immune system and influence the host response to infection. The purpose of this study was to determine the abilities of various phosphorothioate oligonucleotides with cytosine-guanosine-containing motifs (CpG DNA) to activate macrophages to produce nitric oxide (NO) and prostaglandin E₂(PGE₂) and to induce expression of NO synthase 2 (NOS2) and cyclooxygenase 2 (COX2). As little as 0.3 μg of CpG DNA/ml increased NO and PGE₂production in a dose- and time-dependent fashion in cells of the mouse macrophage cell line J774. NO and PGE₂production was noted by 4 to 8 h after initiation of cultures with the CpG DNA, with the kinetics of NO production induced by CpG DNA being comparable to that induced by a combination of lipopolysaccharide and gamma interferon. CpG DNA-treated J774 cells showed enhanced expression of NOS2 and COX2 proteins as determined by immunoblotting, with the relative potencies of the CpG DNAs generally corresponding to those noted for the induction of NO and PGE₂production as well as to those noted for the induction of interleukin-6 (IL-6), IL-12, and tumor necrosis factor. Extracts from CpG DNA-treated cells convertedl-arginine tol-citrulline, but the NOS inhibitorN^G-monomethyl-l-arginine (NMMA) inhibited this reaction. The COX2-specific inhibitor NS398 inhibited CpG DNA-induced PGE₂production and inhibited NO production to various degrees. The NOS inhibitors NMMA, 1400W, andN-iminoethyl-l-lysine effectively blocked NO production and increased the production of PGE₂in a dose-dependent fashion. Thus, analogues of microbial DNA (i.e., CpG DNA) activate mouse macrophage lineage cells for the expression of NOS2 and COX2, with the production of NO and that of PGE₂occurring in an interdependent manner.

Publications with shared reference:

0 publications found